Human Factors - Egress Analysis For High Hazard Occupancies

Human Factors - Egress Analysisfor High Hazard OccupanciesPresented by: Michael J. Klemenz, PE, SFPE

Group H Other SFPE presenters today discussedissues relevant to Group H This presentation addresses means ofegress (MOE) Prescriptive and engineered methods

Group H Defined SECTION 307 HIGH-HAZARD GROUP H 307.1 High-Hazard Group H. High-hazard Group Hoccupancy includes, among others, the use of abuilding or structure, or a portion thereof, thatinvolves the manufacturing, processing,generation or storage of materials that constitutea physical or health hazard in quantities in excessof those allowed in control areas constructed andlocated as required in Section 414

Objectives Means of Egress (MOE) ConceptsPrescriptive Code RequirementsExamplePerformance-Based AlternativesHuman Behavior in Fire EmergenciesQ&A

MOE Defined A continuous and unobstructed path ofvertical and horizontal egress travelfrom any occupied portion of a buildingor structure to a public way.

Alternate definition Engineered building systems thatpermit protected travel from theinterior of a building [on fire] to therelative safety of the exterior [not onfire] prior to the onset of untenable fireconditions.

Components A passive fire protection system Consists of 3 parts:– Exit Access (“non-protected” path)– Exit (“protected” part)– Exit Discharge (safety)

Generally Codes normally prescribe at least twoseparate & remote egress paths Exit access travel distance limits apply Must be maintained for the life of thebuilding

Two Directions Keep in mind While occupants are exiting the buildingduring a fire emergency Emergency service providers are enteringthe building to render aid or mitigate theemergency (fire, EMS, Haz-Mat, etc.)

Objectives Means of Egress (MOE) ConceptsPrescriptive Code RequirementsExamplePerformance-Based AlternativesHuman Behavior in Fire EmergenciesQ&A

Codes & Standards NYS building code Chapter 10 “Meansof Egress” IBC Chapter 10 NFPA 101, “Life Safety Code” OSHA CFR 1910 Subpart E

Occupant Load The number of persons for which themeans of egress of a building or portionthereof is designed

Gross Floor Area The floor area within the inside perimeter of the exteriorwalls of the building under consideration, exclusive of ventshafts and courts, without deduction for corridors,stairways, closets, the thickness of interior walls, columnsor other features. The floor area of a building, or portionthereof, not provided with surrounding exterior walls shallbe the usable area under the horizontal projection of theroof or floor above. The gross floor area shall not includeshafts with no openings or interior courts.

Accessible Moe A continuous and unobstructed way ofegress travel from any accessible pointin a building or facility to a public way.

Exit Access That portion of a means of egresssystem that leads from any occupiedportion of a building or structure to anexit. Normally no fire resistance rating

Exit That portion of a means of egress system which isseparated from other interior spaces of a buildingor structure by fire-resistance-rated constructionand opening protectives as required to provide aprotected path of egress travel between the exitaccess and the exit discharge. Exits include exteriorexit doors at ground level, exit enclosures, exitpassageways, exterior exit stairs, exterior exitramps and horizontal exits.

Exit Discharge That portion of a means of egresssystem between the termination of anexit and a public way.

Public Way A street, alley or other parcel of land open tothe outside air leading to a street that hasbeen deeded, dedicated or otherwisepermanently appropriated to the public forpublic use and which has a clear width andheight of not less than 10 feet It is the final destination for occupants and isassumed to be safe from the emergency in thestructure.

Exit Enclosure An exit component that is separated fromother interior spaces of a building orstructure by fire resistance-ratedconstruction and opening protectives, andprovides for a protected path of egresstravel in a vertical or horizontal directionto the exit discharge or the public way.

Corridor An enclosed exit access component thatdefines and provides a path of egresstravel to an exit. NOT the same as an exit passageway

Exit Passageway An exit component that is separated fromall other interior spaces of a building orstructure by fire-resistance-ratedconstruction and opening protectives, andprovides for a protected path of egresstravel in a horizontal direction to the exitdischarge or the public way.

Common Path Of Travel That portion of exit access which theoccupants are required to traverse beforetwo separate and distinct paths of egresstravel to two exits are available. Pathsthat merge are common paths of travel.Common paths of egress travel shall beincluded within the permitted traveldistance.

Exit Access Travel Distance Exits shall be so located on each story suchthat the maximum length of exit accesstravel measured from the most remotepoint within a story to the entrance to anexit along the natural and unobstructedpath of egress travel, shall not exceed thedistances given in Table 1016.1.

Measurement of Travel DistanceNFPA 101-7.6*.7.6.1* The travel distance to an exit shall be measured on the flooror other walking surface as follows:(1) Along the centerline of the natural path of travel, starting fromthe most remote point subject to occupancy(2) Curving around any corners or obstructions, with a 12 in.clearance therefrom(3) Terminating at (a) Center of the doorway, (b) Other point atwhich the exit begins or (c) exit discharge

Objectives Means of Egress (MOE) ConceptsPrescriptive Code RequirementsExamplePerformance-Based AlternativesHuman Behavior in Fire EmergenciesQ&A

Example Problem Single story, 4000 sf. building Non-separated uses consisting of labs,offices, storage, process and supportspaces Construction type per Table 503 NFPA 13 fire sprinkler system IAW903.2.4.1

Group H Building Class 4 Oxidizers- quantity exceedsTable 307.1.1 for a control area 307.3 High-Hazard Group H-1. Buildingsand structures containing materialsthat pose a detonation hazard

EXAMPLERefer to Board/Easel

Example1. Calculate occupant load2. Evaluate means of egress3. Make necessary corrections

Example1. Calculate occupant load2. Evaluate means of egress3. Make necessary corrections

Occupant Load Occupant load factors in Table 1004.1.1Also seeNFPA 101Table 73.1.2– Industrial areas: 100 gross– Accessory storage areas, mechanical equipmentrooms: 300 gross– Business areas: 100 gross Where an intended use is not listed in Table1004.1.1, the code enforcement official shallestablish a use based on a listed use that mostnearly resembles the intended use.

Occupant Load Assume occupant load factor of 75 sf.gross per the AHJ Occupant load 4000 sf. 75/sf. 53.3 54 occupants

Example1. Calculate occupant load2. Evaluate means of egress3. Make necessary corrections

* Single exitH-1 notpermitted byTable 1019.2Summary of Values for H-1FeatureValueReferenceNumber of Exits2Table 1019.1*Exit Access TravelDistance75’1016.1Common Path of Travel25’1014.3Dead End Corridor20’1017.3Corridor Width44” or per Table 1005.11017.2Exit Remoteness1/3 max. horizontal1015.2.11 hr. w/ 20 min. doorTable 1017.1Corridor FRR

ExampleTABLE 1005.1EGRESS WIDTH PER OCCUPANT SERVEDOccupancyNo SprinklersStairway(in. peroccupant)Other egresscomponents(in. peroccupant)With SprinklersStairway(in. peroccupant)Other egresscomponents(in. peroccupant)Other than listedbelow0.30.20.20.15Hazardous: H-1,H-2, H-3 & H-40.70.40.30.2Institutional: I-2NANA0.30.2

Example1. Calculate occupant load2. Evaluate means of egress3. Make necessary corrections

Ceiling Height & Lighting 1003.2 Ceiling height. The means of egressshall have a ceiling height of not less than 7’-6”1006.4 1006.2 Illumination level. MOE illuminationcontainsdetailedlevel shall not be 1 foot-candle (11 lux) at thephotometricwalking surface level. Power shall be from theandperformancepremises' electrical supply. Provide E-powerrequirements(90 minutes) in MOE components.

Objectives Means of Egress (MOE) ConceptsPrescriptive Code RequirementsExamplePerformance-Based AlternativesHuman Behavior in Fire EmergenciesQ&A

Alternate MethodsEgress Time Hazardous conditionstime Apply where compliance withprescriptive parameters may not bepossible or practical Use FP engineering principles andcomputer modeling to simulate firedevelopment and compare tocalculated egress time from a building

Fire ModelingOne side of the equation ASET (Available Safe Egress Time) is a programfor calculating the temperature and position ofthe hot smoke layer in a single room withclosed doors and windows. Used to determine the time to the onset ofhazardous conditions for both people andproperty.

Fire Modeling DETACT (DETector ACTuation-Time squared) isa program for calculating the actuation time ofthermal devices Used to predict the actuation time of fixedtemperature and rate-of-rise heat detectorsand of sprinkler heads subject to a userspecified fire that grows as the square of time.

Fire Modeling CFAST (Consolidated Model of FireGrowth and Smoke Transport) is amulti-room fire model that predicts theconditions resulting from a userspecified fire within a structure

Fire Modeling FDS (Fire Dynamics Simulator) predictsthe transport of heat and smoke from afire. BREAK1 estimates time until glassbreaks FPEtool is a multi-purpose modelingtool

CFAST Input Parameters Geometrical data describing the roomsand connections Thermophysical properties of the ceiling,walls, and floors Fire as a rate of mass loss Generation rates of the products ofcombustion

CFAST Output Temperature, species concentrationsand thickness of the hot upper layerand the cooler lower layer in eachcompartment Surface temperatures, heat transfer,and mass flow rates

Total Egress Time The other side of theequationTime to NotificationReaction TimePre-evacuation Activity TimeTravel or Movement Time

Time to Notification Fire detection or discoverySignal processingAlert signal or message to occupants72, NationalReceived by occupants? NFPAFire Alarm Code

Reaction Time Time it takes an occupant to perceivethe alarm or fire cue and then decidewhat action to take Depends on what the occupantperceives Immediate danger?

Pre-evacuation Activity Time Time that elapses while the occupant ispreparing to leave or seek refuge Safely shut down plant operations? Make phone calls? Alert others? Secure sensitive files & information?

Travel or Movement Time Time to move to a location of safety Includes horizontal and vertical travel 250 ft/min average speed* foroccupants with no impairments? Significant speed reduction foroccupants with disabilities

Successful MOE Design Time to the onset of hazardousconditions for occupants Total egress time Egress Time Hazardous conditionstime

Objectives Means of Egress (MOE) ConceptsPrescriptive Code RequirementsExamplePerformance-Based AlternativesHuman Behavior in Fire EmergenciesQ&A

Human Behavior The way a person reacts to a fireemergency is dependent on manycomplex and interrelated factors Occupant actions are influenced by theperceived fire threat and observedbehavior in others

Evacuation Studies The earliest documented studies on humanbehavior in the United States involved capacitycounts of the velocity of pedestrian movement forthe New York City design of the Hudson TerminalBuilding in 1901 The first edition of the National Fire ProtectionAssociation’s Building Exits Code in 1927 (whicheventually evolved into NFPA 101 , Life SafetyCode ) was developed from evacuation studiesconducted during the decade since 1917.

Occupant Interviews Scientific, post-fire interviews withpeople have revealed a great deal ofdata on occupants’ actions during thefire Experiments were performed toobserve subjects reactions to fire cues